Control of the supply of liquid fuel to the air charge of internal combustion engines



March 31, 1936. H R RICARDO 2,035,569

CONTROL OF THE SUPPLY OF LIQUID FUEL TO THE AIR CHARGE OF INTERNAL COMBUSTION ENGINES Filed NOV. 22, 1953 D I Q Ei/YVF/VTOP] h a gm m Patented Mar; 31, 1936 UNITED STATES, PATENT OFFICE CONTROL OF THE SUPPLY OF LIQUID FUEL TO THE AIR CHARGE OF INTERNAL COM- BUSTION ENGINES Harry Ralph Ricardo, London, England Application November 22, 1933, Serial No. 699,280 In Great Britain November 30, 1932 10 Claims. (Ci 123-439) This invention relates to multi-cylinder internal combustion engines of the kind in which a combustible charge constituted by a volatile liquid fuel in the form of vapour or finely divided liquid particles and air is ignited by a spark and wherein the fuel is introduced into the air charge at every cycle of the engine by a metering pump, and has for its object to improve the control of the metering pump or pumps so as to tend to maintain the required ratio of fuel to air dur all running conditions of the engine.

In engines of the kind referred to the fuel is admitted to the air charge in such a manner that the fuel is mixed intimately with the air before ignition, the fuel preferably being supplied by a separate metering pump which measuresout and delivers the required quantity of fuel. The advantages of employing metering pumps in the above manner over the use of a carburettor are that approximately the whole of the latent heat of the vapourized fuel is available for lowering the temperature of the mixture within the cylinder so that a greater weight of charge is present in the cylinder at the end of the suction stroke, the compression temperature is reduced thus reducing the tendency for detonation to take place so that a somewhat higher compression ratio may be used, and more uniform distrlbution can be maintained as between the several cylinders of a multi-cylinder engine than is the case where a single carburettor feeds a number of cylinders. Further, the absence ofcombustible mixture within the induction manifold allows of a weaker mixture being used without risk of fire if backfiring occurs, eliminates considerable wastage due to deposition of the liquid on the walls" of the induction passage which tends to take place when a carburettor is used in engines which operate under rapidly varying loads, reduces the tendency for dilution of the lubricating oil with liquid fuel, tends to enable the engine to develop substantial power immediately after starting up from cold, and eliminates difliculties due to the fact that with a carburettor the induction passage walls under certain running conditions are wet and under other condi-- tions become dry so that on changing from one condition to the other either surplus fuel enters the air due to the drying off of the induction passage or fuel is taken from the vapourized charge by reason of the wetting of the induction passage walls. Moreover, losses in the-charge density and the tendency to detonate resulting from preheating of the mixture are reduced or eliminated.

when employing the metering pump system for providing the combustible charge in engines of the kind in' question having a substantially fixed ratio of torque to speed, for example to marine or aircraft engines, a satisfactory ratio between the quantity of fuel and air can usually be obtained by the provision of a mechanical linkage interconnecting the metering member controlling the quantity of fuel delivered by the metering pump or pumps and the throttle in the induction pipe, but when employing this system in engines such as those used on road vehicles in which there is no definite ratio between torque and speed, there is difllculty inmaintaim'ng the correct proportion of fuel to air under the vary-= *lll ing conditions, which render a simple mechanical linkage impracticable, and the object of the present invention is to overcome these difliculties. 1

To this end according to the present invention not only is fuel delivered separately to the air charge for each cylinder but means are provided whereby the quantity of fuel delivered by the metering pump or pumps is controlled in ac cordance with the pressure in the inductionpas sage, and since'at all speeds under 'normal conditions of positive load it has been found that, assuming constant atmospheric pressure, the absolute pressure in the induction passage is ap proximately proportional to the weight of air entering each cylinder per cycle, it will be seen so that with such a control a substantially constant ratio of fuel to air can be maintained:

Although, as stated, the absolute pressure in so the induction passage is approximately proportional to the'weight of air entering each cylinder per cycle under normal conditions of positive load, yet when over-running occurs, that is to say when, in the ease \of a motor vehicle, the vehicle is driving the engine as when decelerating or going downhill, it is desirable that the fuel 40 supply should be completely cut off since the depression in the induction pipe when over-running is little-greater than when idling at a slow speed, this depression when idling being nearly at a minimum and only a slightly increased depression being obtained if the vehicle over-runs the engine. Thus unless some special means are provided, with apparatus controlled according. to this invention by the depression in the induction pipe, the quantity of fuel delivered per cycle when over-running occurs would be substantially the same as when idling, althoughv the weight of air drawn in to each cylinder per cycle would be inversely proportional to the engine speed. From this it follows that when over-running at 56 high speed, whereas the weight of air taken in by the engine would be virtually constant for any given time interval, the fuel delivered for the same time interval would be proportional to the speed with the result that each cylinder wouldreceive an excessively over-rich mixture under conditions when so little air charge is drawn in on each induction'stroke that the mixture might not ignite, thus causing wastage of fuel and dilution of the'oil in the cylinders with the fuel.

The above difllculty could be overcome by employing a system of mechanicallinkage so that the very small increase in depression in the induction pipe. between the depression when idling and the depression when over-running would cause a comparatively large movement of the member controlling the quantity of fuel delivered by the metering pump or pumps whereby this small increase in depression would result in a complete cutting .ofi of the fuel supply, Such an arrangement, however, would be very delicate and difllcult to maintain as well as involving mechanical complication, the difiiculty being increased by the fact that when idling a comp arative'ly rich mixture is required as compared with when developing positive-torque under normal running conditions.

' Preferably, therefore, with a view to overcoming the above difliculty, according to a further feature of the present invention means are provided whereby inert gaseous products of combustion from the engine are permitted to enter the induction pipe when the pressure therein is low so as to raise the absolute'pressure in the induction pipe when idling without increasing the quantity of air supplied to the engine. In this way, while .the depression in the induction pipe can be re-' uiantlty of.-fuel delivered by the meterin'g pump or pumps in accordance with the pressure in the induction passage and permitting exhaust gases to enter the induction passage when the premure therein is low, it will be possible in a simple manher to cause this-control to operate so that a fsuillcient quantity of, fuel is delivered when the depression is that for idling whereas this fuel can-be completely out ofl when any considerable degree of over-running takes place.

" present invention relates, whereas during nor- Again, in engines of the kind to which the mal cruising conditions when maximum torque is not required it is desirable to employ aratio -of fuel to air which is economical under all conditions of speed and load, that is to say either a chemically correct ratio or a ratio having a slight excess of air over the, chemically correct ratio, when the maximum torque is required, as when accelerating or, hill climbing, a somewhat richer mixture having, say, 15% to 25% excess fuel over the chemically correct mixture is desirable.

' To provide for this, according to a still further feature of the present invention, the arrange- .ment may be such that whereasthe quantity of fuel delivered by the metering pump or pumps is controlled in accordance with the. absolute pressure in the induction passage so'that under cruis- 3 ing conditions a mixture which .15-19-Ppmximate1y chemically correct or hasa slight excess of air :municates with the atmosphere.

over the chemically correct mixture is supplied,

the final movement of the throttle into its fully open position effects an adjustment of the pump control mechanism so as to cause the pump or pumps to deliver a slightly larger proportion of fuel in relation to the air charge, for example such as to produce a mixture having between 15% and 25% excess fuel over the chemically correct mixture.

It will therefore be seen that by controlling the pump delivery inaccordance with the absolute pressure in the induction pipe, providing means for admitting exhaust gases to the induction pipe when the pressure therein is low and means whereby the final opening movement of the throttle valve eflects an adjustment to cause an increasein the quantity of fuel dehvered by the pump or pumps, it is possible not only to provide for the delivery of an economic mixture for normal running conditions but to provide a slightly over-rich mixture when maximum torque is required and to ensure that when any considerable degree of over-running takes place the supply of fuel by the fuel pumps will be completely.

out off. Further, when exhaust products are admitted as described above, the variation in induction passage pressure between that at idling and that when developing say of the maximum positive torque, is reduced while a relativeiy large increase iri the quantity of airadmitted takes place when the throttle is moved.- from its idling to, say, its 20% torque position.

Thus the slightly over-rich mixture usually desir'-.

Figure 2 is a plan of the modified construction.

ah the construction illustrated 'in Figure l, the engine, A is provided with four inlet passages B communicating respectively with the inlet ports of the. four cylinders A A, A A and leading from an induction pipe B the inlet of air to which is controlled by a throttle valve 0 adapted to be actuated by a lever C The engine has an exhaust manifold D which communicates with the induction pipe B through a. passage D having a metering orifice, indicated at D*, arranged therein.

Driven fromthe erankshaft E of the engine, for example through chain wheels E E and 'a chain E is a fuel delivery pump F having four cylinders connected by delivery pipes F respectively to the four inlet passages B of the engine.

The fuel pump F is provided in known manner with a control member G whereby the quantity offuel delivered -on each plunger delivery stroke can bevaried by moving this member lon-' gitudinally. The member G is connected to a piston H arranged in a cylinder H one end of which communicates through a passage ,H with the induction pipe B while its other end com- The control member G has rigidly secured to it a collar J on the opposite sides of which act the adjacent ends of two compression springs J the opposite ends of which bear against fixed abutments J,

' J so as tend normally to maintain the piston in, the position shown in Figure '1.' The piston a. H isconneeted to a piston rod K passing through tion to that of theiengine that-fuel is delivered: to the inlet-pipe associated with each cylinder during each suction'stroke of 1 the'piston in such" a, gland at. the end of the cylinderH adjacent to the lever .0 and the arrangement is'such that towards the :end of the movement of thelever C to open'the throttle valve C, this lever tive movement of the control member G of .the

fuel pumpin aj directionto increase. the quantity of fuel delivered. The timing of theiuel pump F i's'suchin'rela" cylinder; and the operation of the apparatus" is as follows 7 The'right hand face 'of' thepiston-II is 'sub-. ject to atmospheric pressure and during opera-. tion of the engineit will be seen that the left hand face of the piston H will be subject to the depression in the induction pipe, which iii-turn will be dependent partly upon the extent of-open-w ing', of the throttle valve and partly upon, the speed of the engine. 7 The piston 'H' will thus tend to occupy a position-corresponding to-the; de-

- ciated'tha t thef le'ver C does not normally-act 3 on the piston, rod,' since movement-oi, the lever 3o.

pression in the induction pipe. It will be appretowards the piston rod opens the 'throttle' and thus reduces the'deprfession in theinduction pipe; with the result that the piston and piston rod. moveto the right,- and it is only'when the throttle valve is practically fully open so that thereis' no substantial depression in the induction pipe,

that the lever C comes into. contact with the' pistonrod K and can .then act directly thereon to increase the quantity of fuel delivered and 1 thus.

give a slightly over-rich inixturewhen absolutely. 'full power is required. 'Thus while'du'ringnormal operation when maximum power output is,

' not required the control member G of the fuel pump is .moved' in accordance-with the induction pipe pressure so that the fuel pump delivers a at all times aquantity of fuel substantially proportial to the weight ofairenteringthe-cylinders,"

. when maximum power output is desired the lever C can over-ridethe' action-of the';depression' in the induction'pipeon the piston to'enable tion pipe through the pipe the somewhat over-richmixtureqrequired to be obtained. N

' Further, it will be is closed and the depression in'the induction pipe thus increases the quantity of inert. ex'- haust .gaseswhich will be drawn into the induc arrangement issuch that although'the quantity of air drawn in through the throttle-valve C during idling is substantially that required for' idling, thepressure' in the induction pipe is still appreciably above normal idling pressure owing .to the "quantity of inert gases which are free to j enter through the pipe B; When, however, with hicle, the depression in the induction pipe falls to substantially idling depression and-this moves the throttle valve in its idling position the speed of the engine is above idling speed, c. g. when the engine is being driven by the vehicle as when decelerating'or goingdownhill in acmotor vethe piston H so as completely to shut off-the delivery of fuel by the fuel pump. Thus,- while the correct quantity of fuel for idling is delivered when theengine is idling, the supply-of fuel is completely out oif when, with the throttle valve in its idling position, the engine is rotating seen, that as thezthrottle C D increaseaand the idling speed.

-' Injthe modified construction shown'in Figure 2, the arrangement is generally similar to that shown in Figure 1' except that the induction pipe B has incorporated in it a; venturi B the throat v of whichhas connected toit-thepipl-P. With can act on the 'pistonfrod K so as to c'auseposithis pro posal the position of the piston H, and

4 hence the quantity'offuel injected, is dependent to some extent not onlyon the actual depression in the induction-pipe but also on the rate of flow 01'; airthrough this pipe, so" that-when "the engine is running at high speed with fullfthrottle opening and the actual weight of air drawn'into the cylinder per cycle may, due 'to :thethrottling effect of the inlet valves; b -somewhat les'sthan V "at full throttle opening at lowerspeed,-the desired uantity ofiuel in proportion yto the air" tends, to be maintained. r

. In some cases as an alternativej to providing; the pipe- D 'between the exhaustmanifold and the induction 'pipe, gaseous products 'ofcombustion may be admitted to theinduction'pa'ssage when 1 the pressure therein is low, byoperating. the .valves of'the engin'e-in'such a mannerthatthef inlet valve opens at-a moment Subs'tantiallyibe- 'fore that at which the exhaust 'valiveflcloses so that when thev pressure the 1 induction passage is low gaseous-products of combustion-will.

.flow from each cylinder through the'inletf-portinto the induction passage during the initial part of each opening period of theinlet -valve,

convenient alternative-to that diagrammatically shownthe control member of the pump may be operated through a lever havinga movable fulcrum' and the final movement-of the throttle valve into 'its fully open position, effects a'nad-A justment of this fulcrum so that when the throt-' s :45 of. fueli'sdelivered by the pump forany given ina duction pipe-pressuref I i r Again, in some cases the fuel, instead of being delivered'to the inlet pipe of each cylinder, may .be delivered-direct to theinterior of the cylinderv itself. 1

M y f What .Iclaim 'as"my inventionanddesire to secure -by Letters Patent i's:

tle valve is fully open a slightly greater quantity 1.'A multi-cylinder-internal combustionjen- I,

gine of the va'pourized charge spark ignition type,

including in combination an induction passage, a-

throttle va-lvecontrollingthe air inlet oithe in duction passage, a metering pump driven by the the air charge 'i'oreach cylinder to form"a.com:

the quantity of fuel delivered by the metering a'membens'u'biect to and movable in -ac-' cordance with variations; in' the pressure 'in' theinduction'passagejmeanspwhereby movement of the saidm ember. effects movement of the meterj ing pump control member-to reduce the quantity;

of fuel deli'vered'when the induction'passagepressure is reduced and to increase the quantity of fuel delivered when the induction passage pressure. increases, and meansior. delivering gase ousproducts of combustion from the engine to U the. induction'passage insubstantial quantity when the pressure'thereinis low only, for the I purposeset-forthfl 2. A' mum cyli'ndei- 'internal combustion ell-- gine of the vapourized charge spark ignition type,- including in combination an induction passage an exhaust passage, a-throttle valve controlling the air "inlet'of the induction passage, a metering pumjp driven by-theengine for introducing liquid fuel separately into the air charge for eachcylinder to form a combustiblefmixture; a control '-member for varying the quantity of fuel delivered by 'themetering pump; 'a-membr sub- 'ject to and movable in accordance with variameans whereby movement-of the said effects movement of the metering p'ump'control .and to increase- 'the' quantity of fuel tions in the pressure in the induction passage,

member member to reduce the quantity of fuel delivered when the induction passage pressure is reduced delivered when the-induction passage pressure increases,

and a transfer passage constituting a cornmuni- 5 cation between the induction passage and the exhaust passage of the engine so as to permit entry of gaseous products of combustion into'the" induction passage in substantialquantity when pressure therein'is low only.-'

3. A muIti-cylinder internal combustion engine ofthefvapourized charge-spark ignition type,

. combustible mixture, a control 3 in'gjthe 1quantityof' fuel delivered by the meter-t pumpdriven by.

into the air charge for eachcylinder to form a memberfor varyingpum'p, a member subject to and movable in accordance with variations in the pressure in the induction passage, means wherebymovement of the said membereflects movement of the meter-I ing pump control member to reduce the quantity of. fuel delivered when the induction passage pres-- the. quantity of accordance with variations in the {pressure in fuel delivered when the induction pressure increases, a, throttle valve control member, and

sure is reduced and to" increase 7 meanswhereby the final-part only of the move- Zment of this member in "a direction to open the throttle valve applies a' force to the metering pump control member to move quantity of fuel delivered thereby'above that ."which would be delivered if the metering pump" a control member wereleft under the sole control 150 of the member'whichis movable in accordancewith variations in-the-pressure in'the induction pas age ii j 4. A multi-cylinder' internal 1 combustion engine of the vapourized charge spark ignition type,

-' a throttle valve controlling the air inlet of including I in combination an induction passage, 'the induction passage, a metering pump driven by the engine for-introducing liquid fuel separately into the air charge for each cylinder 'to form -'a combustible mixture, ajcontrol member -for'vary-' ing the quantity of fuel delivered by the metering pump, a member subject to and movable vin ac- Y jcordance with variations in the pressure in the induction passage, means whereby movement of the said member effects movement of the metering pump control member to reduce the quantity of fuel delivered when the' induction passage pressure is reduced and to increase the quantity of fuel delivered when the induction passage pressure increases, means for delivering gase- 'ous' products of combustion from the engine to the induction passage; I in "substantial quantity when thepressure therein is low'only, athrottle valvecontrol memb'en'and means whereby the'final part only of the movement of thifsimember, in a fuel separately into theair means whereby movement of effects movementof the metering pump-control it' to;i'ncrease the a direction to open the throttleivalve applies a force to the metering 'pumpcontrol member to move it to increasethe quantity of fuel delivered thereby above thatwhich would be delivered if I movable in accordance'with variations in the pressure in the induction passage, v 5. 'A multi-cylin'der internal combustion engine of the vapourized charge spark ignition type,

including in combination an induction passag'e,

an, exhaust passage, a throttle valve coiit'rolling.

the air inlet of the in'duct'ion passage, a metering pump driven'by the engine for introducing-liquid charge for: each cylinder to'form a combustiblemixture, a con-Q 1 trol memberfor varying the quantity'of .fuel delivered by the metering pump,'a member sub'-.,

ject. to and movable in accordance with varia-' tions in the pressure in the induction passage,

member to'reduce the quantity-offuel delivered when the inductionpassa'ge pressure is reduced and'-'to-increase the quantity of fuel delivered when the inductionpassage pressure increases,

' a transferpas'sage constitutinga communication between the induction passage and the exhaust passage of the engine so as to permit entry of gaseous products of combustion into the induction passage insubstantial quantity when pressure thereinis low only, a throttle valv'e control.

vmember, and means whereby the'final-part only of 'themovement of this member in a direction to open the. throttle valve applies a force to'the metering pump control member to'move it to increase the quantityof fuel delivered thereby above that which would be delivered if the metering pump control member were left underthe sole control of the member which is movablein the induction passage.

- 6. A multi-cylin'der' internal-combustion engine of the vapourizedcharge spark ignition type, including in combination 'an' induction passage, a venturi constituting part of the induction passage, a throttle valve controlling the air inlet ,--of the induction passage, a metering pump driven by the engine for introducing liquid fuel separate- .ly into the air charge for each a member subject to andmovventuri, and means to increase the quantity of fuel delivered when the said member cylinder to form a combustible mixture, 'a control member} for I varying the. quantity of fuel metering pump, v able in accordance with variations in the pres sure at the throat of the 7 'whereby movement of the said member effects movement of the metering pump control meme her to reduce the quantity of fuel delivered when the pressure at the Venturi throat/is reduced and delivered by the 7. A multi-cylinder internal combustion engine i of theyapourized charge'spark ignition type, in cluding in combination aninduction"passage a venturi constituting; part of thev inductionf pas- Saga. 8. throttle valve controlling the air inlet of the induction passage, a metering amper-wen by'the engine for introducingffliqiiid'fuel sep'a- "control member I rately into the air. charge for -eacli: cylinder to form a combustible mixture, a for varying the quantity of fuel metering pump, a member subject to and movable in accordance with variations'in' the throat of the venturi, means the lpressure at. I I :ereby 'move{ ment ofthe said member eflect's movement of the" quantity of fuel delivered when the pressure at the Venturi throat is reduced and to increase the quantity of fuel delivered when the pressure at s the Venturi throat increases, and means whereby gaseous products of combustion from the engine when the pressure therein is low, for the purpose set forth.

gine of the vapourized charge spark ignition type, including in combination an induction passage,

, a venturi constituting part of the induction passage, a throttle valve controlling the air inlet ofthe induction passage, a metering pump driven by the engine for introducing liquid fuel separately into, the air charge for each cylinder to form a combustible mixture, a control member for varying the quantity of fuel delivered by the sure at the throat of the venturi, means whereby of the metering pump control member to reduce the quantity of fuel delivered when the pressure at the Venturi throat is reduced and to increase the quantity of fuel delivered when the pressure at the Venturi throat increases, and a transfer passage constituting a communication between the induction passage and the exhaust passage of the engine so as to permit entry of gaseous products of combustion into the induction passage when pressure therein is low.

9. A multi-cylinder internal combustion engine of the vapourized charge spark ignition type, including in combination an induction passage, a venturi constituting part of the induction paspatentee.

[Qflicial Gazette June 15, 193?.].

\ 2035,1569 'metering pump control member to reduce the are permitted" to enter the induction passage.

8. A multi-cylinder internal combustion I enmetering pump a member subject to and movable in accordance with variations in the presmovement of the said member efiects movement sage, a throttle valve controlling the air inlet of sure at .the throat of the venturi, means whereby movement of the said member efiects movement ofv the metering pump control member to reduce the quantity of fuel delivered when the pressure at the Venturi throat is reduced and to increase the quantity of fuel delivered when the pressure at the Venturi throat increases, a throttle valve control member, and means whereby the final part of the movement of this member in a direction to open the throttle valve eflects -movement of the metering pump control member to increase the quantity of fuel delivered thereby above that which is delivered for corresponding induction passage pressures with smaller throttle openings.

10. A multi-cylinder internal combustion engine of the vapourized charge spark ignition type,

including in combination an induction passage, a venturi constituting part of the induction passage, a' throttle valve controlling the air inlet of the induction passage, a metering pump driven by the engine for introducing liquid fuel separately into the air charge for each cylinder to form a combustible mixture, a control member for varying the quantity of fuel delivered by the 'metering pump, a member subject to and movable in accordance with variations in the pressure at the throat of the venturi, means whereby move ment of the said member effects movement of the metering pump control member. to reduce the quantity of fuel delivered when the pressure at the Venturi throat is reduced and to increase the quantity of fuel delivered when the pressure at the Venturi throat increases, means whereby gaseous products of combustion from the engine are permitted to enter the induction passage when the pressure therein is low, a throttle valve control member, and means whereby the final part-of the movement of this member in a direction to open the throttle valveeifects movement of the metering pump control member to increase the quantity of fuel delivered thereby above that which is delivered for corresponding induction passage pressures with'smaller throttle openings.

HARRY RALPH 'R ICARDO.

DI SOI AI M ER 2,035,569.Hdrry' Ralph Ricardo, London, England. CONTROL OF THE SUPPLY 0F LIQUID FUEL o THEAIR CHARGEJOF INTERNAL COMBUSTION ENGINES. Patent dated March 31, 1936. Disclaimer filed May 18, 1937, by the Hereby enters this disclaimer to claim 6.

quantity of fuel delivered when the pressure at the Venturi throat is reduced and to increase the quantity of fuel delivered when the pressure at s the Venturi throat increases, and means whereby gaseous products of combustion from the engine when the pressure therein is low, for the purpose set forth.

gine of the vapourized charge spark ignition type, including in combination an induction passage,

, a venturi constituting part of the induction passage, a throttle valve controlling the air inlet ofthe induction passage, a metering pump driven by the engine for introducing liquid fuel separately into, the air charge for each cylinder to form a combustible mixture, a control member for varying the quantity of fuel delivered by the sure at the throat of the venturi, means whereby of the metering pump control member to reduce the quantity of fuel delivered when the pressure at the Venturi throat is reduced and to increase the quantity of fuel delivered when the pressure at the Venturi throat increases, and a transfer passage constituting a communication between the induction passage and the exhaust passage of the engine so as to permit entry of gaseous products of combustion into the induction passage when pressure therein is low.

9. A multi-cylinder internal combustion engine of the vapourized charge spark ignition type, including in combination an induction passage, a venturi constituting part of the induction paspatentee.

[Qflicial Gazette June 15, 193?.].

\ 2035,1569 'metering pump control member to reduce the are permitted" to enter the induction passage.

8. A multi-cylinder internal combustion I enmetering pump a member subject to and movable in accordance with variations in the presmovement of the said member efiects movement sage, a throttle valve controlling the air inlet of sure at .the throat of the venturi, means whereby movement of the said member efiects movement ofv the metering pump control member to reduce the quantity of fuel delivered when the pressure at the Venturi throat is reduced and to increase the quantity of fuel delivered when the pressure at the Venturi throat increases, a throttle valve control member, and means whereby the final part of the movement of this member in a direction to open the throttle valve eflects -movement of the metering pump control member to increase the quantity of fuel delivered thereby above that which is delivered for corresponding induction passage pressures with smaller throttle openings.

10. A multi-cylinder internal combustion engine of the vapourized charge spark ignition type,

including in combination an induction passage, a venturi constituting part of the induction passage, a' throttle valve controlling the air inlet of the induction passage, a metering pump driven by the engine for introducing liquid fuel separately into the air charge for each cylinder to form a combustible mixture, a control member for varying the quantity of fuel delivered by the 'metering pump, a member subject to and movable in accordance with variations in the pressure at the throat of the venturi, means whereby move ment of the said member effects movement of the metering pump control member. to reduce the quantity of fuel delivered when the pressure at the Venturi throat is reduced and to increase the quantity of fuel delivered when the pressure at the Venturi throat increases, means whereby gaseous products of combustion from the engine are permitted to enter the induction passage when the pressure therein is low, a throttle valve control member, and means whereby the final part-of the movement of this member in a direction to open the throttle valveeifects movement of the metering pump control member to increase the quantity of fuel delivered thereby above that which is delivered for corresponding induction passage pressures with'smaller throttle openings.

HARRY RALPH 'R ICARDO.

DI SOI AI M ER 2,035,569.Hdrry' Ralph Ricardo, London, England. CONTROL OF THE SUPPLY 0F LIQUID FUEL o THEAIR CHARGEJOF INTERNAL COMBUSTION ENGINES. Patent dated March 31, 1936. Disclaimer filed May 18, 1937, by the Hereby enters this disclaimer to claim 6. 

